1. Field of the Invention
The invention relates to a document holder more particularly to an expansible document holder.
2. Description of the Related Art
FIGS. 1 and 2 illustrate a conventional document holder 1. The conventional document holder 1 includes a rectangular base wall 105 having left and right lateral edges and upper and lower edges, left and right lateral flaps 107 connected to the left and right lateral edges of the base wall 105 respectively along left and right folding lines 103, and lower and upper flaps 106, 104 connected to the lower and upper edges of the base wall 105 respectively along bottom and top folding lines 102, 101. The left and right lateral flaps 107 and the lower and upper flaps 106, 104 are foldable relative to the base wall 105, and cooperatively confine a document confining space thereamong. An elastic cord 108 has opposite ends anchored to the base wall 105, and includes left and right cord portions disposed on an outer surface of the base wall 105. The left and right cord portions are stretchable to overlie corner portions of the upper flap 104 so as to retain the upper and lower flaps 104, 106 and the left and right lateral flaps 107 in a document confining position, as best shown in FIG. 2. However, the cord portions of the elastic cord 108 are easily removed from the upper flap 104 when the conventional document holder 1 is being carried. Moreover, the conventional document holder 1 cannot receive a relatively large amount of documents, thereby resulting in inconvenience during use.
Therefore, the object of the present invention is to provide an expansible document holder that permits secure engagement between left and right lateral flaps and a lower flap.
According to the present invention, an expansible document holder includes a rectangular base wall, left and right lateral flaps, and lower and upper flaps.
The rectangular base wall has left and right lateral edges opposite to each other in a longitudinal direction, and upper and lower edges opposite to each other in a first transverse direction that is transverse to the longitudinal direction. The base wall further has inner and outer surfaces opposite to each other in a second transverse direction that is transverse to both the longitudinal direction and the first transverse direction.
The left and right lateral flaps are connected to the left and right lateral edges of the base wall respectively along first left and right folding lines that extend in the first transverse direction.
The lower and upper flaps are connected to the lower and upper edges of the base wall respectively along first bottom and top folding lines that extend in the longitudinal direction.
The left and right lateral flaps and the lower and upper flaps are foldable relative to the base wall to a document confining position, wherein the left and right lateral flaps are superposed on the inner surface of the base wall, wherein the lower flap and the left and right lateral flaps overlie each other, wherein the upper flap overlies the left and right lateral flaps and the lower flap, and wherein the left and right lateral flaps, the lower and upper flaps and the base wall cooperatively confine a document confining space thereamong.
The lower flap has opposite lateral portions that are disposed in an overlying manner with respect to the left and right lateral flaps in the document confining position. One of the left and right lateral flaps and the lateral portions of the lower flap in each overlying pair is formed with a tab slot. The other one of the left and right lateral flaps and the lateral portions of the lower flap in each overlying pair is provided with an anchoring tab that extends through the tab slot so as to inter-engage the lateral portions of the lower flap with the left and right lateral flaps.